ID   2.3.2.24
DE   (E3-independent) E2 ubiquitin-conjugating enzyme.
AN   E3-independent ubiquitin-conjugating enzyme E2.
CA   S-ubiquitinyl-[E1 ubiquitin-activating enzyme]-L-cysteine + [acceptor
CA   protein]-L-lysine = [E1 ubiquitin-activating enzyme]-L-cysteine + N(6)-
CA   monoubiquitinyl-[acceptor protein]-L-lysine.
CC   -!- The enzyme transfers a single ubiquitin directly from an
CC       ubiquitinated E1 ubiquitin-activating enzyme to itself, and on to a
CC       lysine residue of the acceptor protein without involvement of E3
CC       ubiquitin transferases (cf. EC 2.3.2.26, EC 2.3.2.27).
CC   -!- It forms a labile ubiquitin adduct in the presence of E1, ubiquitin,
CC       and Mg(2+)-ATP and catalyzes the conjugation of ubiquitin to protein
CC       substrates, independently of E3.
CC   -!- This transfer has only been observed with small proteins.
CC   -!- In vitro a transfer to small acceptors (e.g. L-lysine, N-acetyl-L-
CC       lysine methyl ester) has been observed.
DR   Q2TA10, UB2D1_BOVIN;  P51668, UB2D1_HUMAN;  P61080, UB2D1_MOUSE;
DR   D3ZDK2, UB2D1_RAT  ;  Q1RMX2, UB2D2_BOVIN;  P62837, UB2D2_HUMAN;
DR   P62838, UB2D2_MOUSE;  Q06AA9, UB2D2_PIG  ;  P62839, UB2D2_RAT  ;
DR   P62840, UB2D2_XENLA;  Q3ZCF7, UB2D3_BOVIN;  P61077, UB2D3_HUMAN;
DR   Q4R5N4, UB2D3_MACFA;  P61079, UB2D3_MOUSE;  Q5R4V7, UB2D3_PONAB;
DR   P61078, UB2D3_RAT  ;  P51965, UB2E1_HUMAN;  P52482, UB2E1_MOUSE;
DR   P49427, UB2R1_HUMAN;  Q8CFI2, UB2R1_MOUSE;  Q32PA5, UBE2C_BOVIN;
DR   Q9VTY6, UBE2C_DROME;  O00762, UBE2C_HUMAN;  Q4R9D1, UBE2C_MACFA;
DR   Q9D1C1, UBE2C_MOUSE;  Q95044, UBE2C_SPISO;  P56616, UBE2C_XENLA;
DR   Q32LN1, UBE2H_BOVIN;  P62256, UBE2H_HUMAN;  P62257, UBE2H_MOUSE;
DR   Q9C0C9, UBE2O_HUMAN;  Q6ZPJ3, UBE2O_MOUSE;
//